/Engine/Source/Runtime/GameplayTags/Classes/GameplayTagContainer.h
Returns true if this is a valid gameplay tag string (foo.bar.baz). If false, it will fill
True if this can be added to the tag dictionary, false if there's a syntax error
static bool IsValidGameplayTagString ( const [FString](API\Runtime\Core\Containers\FString) & TagString, [FText](API\Runtime\Core\Internationalization\FText) * OutError, [FString](API\Runtime\Core\Containers\FString) * OutFixedString )